Connector with conversation timing



Dec. 10, 1957 E. H. GATJzl-:R'r 2,316,172

CONNECTOR WITH CONVERSATION'TIMING Filed July 9, 195e s sheets-sheet 1 Dec. 10, 1957 E. H. GATZERT CONNECTOR WITH coNvERsATIoN 'rn/Imc;

Filed July 9, 1956 Rmeuie GENERATOR SIG 5 PSOE; vz-EC. 202200 3 O... I lf T 3 T 2 l I H w w H w w \B G l 2 M m ...u B 3 3 3 3 m f 3 I T A 3 I I I l I I l I /I I I IRI 3 v Y 3 3 ll 2 w 5 m I 2 3 u 3 W 3 X f M N S N1- I 6 Y 2 3 sda-fn PRELIMINARY DELAY Dec. 10, 1957 E. H. GATzERT 2,816,172

CONNECTOR WITH CONVERSATION TIMING Filed July 9, 1956 3 Sheets-Sheet 5 FIG. 4

2,816,172 CONNECTOR wrrn corsvnnsnjcr on:TIMING:A

Ernest H. Gatzergltnchcster, N. Yaassgnorr toGe'neral DynamicsY Corporatiomr Rochester, tN. Y., ,jaijcorporm tion ofDelawarL Application July 9,44 1956, SeraLNo.. 596,692

` mams. (ct-179:18):

My invention is concernedwith telephone systems in generaland more particularly withvconnectorbori nal selector circuits suitabiefor@-use=.in-` so-cal1ed-1stepby-step typetelephone systems.

In the past, connector circuitshave beengmade-which are capable ofdeterminingfwhether'or notwa selected'il-ine circuit terminationis in busyl condition. SuchV connectors have beenv supplied with features providing i for (l) selecting sig'nalsfor` transmission I to selecte'd line circuits and subscriber lines, and? (2)v timing `connections established through the communication channel` of the selector. In order to providef'these` featuress-itfhas been the practice to' provide separa-teconnecting-oractuating relays individual to theV connector apparatusassociated with each feature. This practicel increasesl the number ofrelaysindivi'dual to each connector andi-isobjectionable because the cost of "each connector4 is increased correspondingly.

Accordingly, it is an object offzmy invention to provide a new and improved `connector and circuit.

Another object of my invention is to provide a new and improved 'connector circuit'in which the -number of relays is minimized. f

Another object of my invention is to provide a new and improved connector in which yone relay 'isnused for three different vfunctions such as conducting lbusy test,ringing control, and timing control functions.

I accomplish these and other objects in a telephone system having a connector circuit and switch. The switch has a set of wipers and a plurality of'terminal sets disposedfor engagement by the wiper set. Apparatus such as a line circuit and subscriber lines is` individually connected to each of the terminal' sets. Means is provided for independently changing each lof the terminal sets from its normal, idle condition to a busy condition when the corresponding line andlinecircuitV isin use. rfhe connector also includes means for di'rec'tiveljy advancing the wiper set into engagement with any oneof'the terminal sets in order to malte other means,fincluding the wiper set, of the connector, ultimatelyeffective for'- eX- tending a communication channel through` the selector to a selected terminal set.

According to the invention, the connector circuit also includes a special, multi-purpose'rv relay khaving a winding and a plurality of contacts.` Following the engagement of one of the terminalv sets by the'wiper set,. first connecting meansis operative for making thespecial relay eiective to determine the busy or idlel condition of the selected set of terminals. I-nl the event` that: the relay indicates that the selected terminal set.` isin busy condition, certain contacts on the relay are eiective for indicating the busy conditionofthe selected terminal set by rendering thecOmrnuni'CatOn channelfextendingmeans inoperative, thereby preventing the extension of such a connection to a busy sel'ectedterminal set.

" In order to transmit*distinctivefsignal's to the apparatus terminated on a selected; terminal'setiasouree of sig- 2,816,172 Patented Dec. 10, 1957 nalingcurrent. is provided. Within the connector, signaling. means, including certain; other-vcontacts on the special relay are effective for connecting the currentv source to the selectedy one of the terminal'sets. Other means associated with the' signal source are thereafter effective in. response to theoperation ofthe channelfextending meansi-foncontrolling they operation ofthe -special relay -in order to carry out thedistinctive signalingoperations The connector circuit alsoincludesmeans operative-in response to the transmission to the selector-of anoifhookA supervisory; signahfrom the line eonnectedto; the selected terminal set -etlectivei intthe 5 well-known: manner foryrenderin'g the:` signaling: means ineffective and-,for vcompletingthe communication channel. Another sourcefis eiectivey for tranSmittmg-timedsignals to the. connector. Means:V operativey inl response to' the-operation. oli` the supervisory.y signal responsive: means are` thereafter. operative under lthe 1 control of those ltiming' signals for -causing:-the-aforesaidm speciali relay'ito be=reoperatedl aupredet'err'nined timeinterval: afterV the receipt offtheclhoolcsupe-rvisory signal. Stillother contacts onv the-spe ciali relay'iare thereupon e'ective'; forfblockingtheacommun-ication channeI inorder tof preventy the transmission off speech signals over the communication channel i* For faybetterunderstanding of my invention as: set forth irr-the following description: and the appendedtclaims, reference is-rnade tothe-attached drawings, in which:

Fig.l l'shows, in block form, atypical telephone system including a connector which incorporates-'theopreferred embodiment of my invention;

Fig. 2 shows, in block" form, equipment for originating a cali throng-h the telepl1one\systemofeFig. 1;andf, in schematicy form, ay part of the connector incorporating the preferred' embodiment of my invention; and

Figs.v 3- and 1f/show, in schematic form; theremainder of the connector incorporatingthe preferred embodiment of" my invention. Fi-g. 4 additionally-includes', in-block form,`apparatus to which Vthe connector has access: p

Power for operating the system is-drawnfromeseveral sources.` The iirst of these is a-battery, themost positive plate or terminal of which is connected. to vgrot-1nd and is hereafterreferred to in the written-description'-as ground and in the drawings as -|-)f. Theother;V ungrounded terminal'or-platel of thebattery is l-reierredlto in the written description as battery and in the drawings as A second source offpower is the Vwellunderstood alternativing current ringing generator connectedin series with abattery. Again,` the Iriostpositve plate of the battery is connected togroundgandei's-hereafter referred to as ground in*thewritten'description, and asv (-1-) in the drawings. The ungroundedf side-of the battery-generator combination is referred Atogeasringing generatofin both the drawings and written description. l

ICC

Extending a connection t0 the connectar In order to extend a call` from` a calling subscriber station, such as 21,- well-knownI hookswitch means atfthe station is effective upon the removal of -the `telephone from its hoolcswitchfor causingrapparatus (not shown) to extend a connection froml the telephone'` station through apparatus individualto the. calling station, such as linel circuit LC21, to a selector, suchY as 22.y Thereafter, the transmission of a directive Vsignalfto selector 22` is eiective for advancing the selector-wipers, `shown collectively as W22, to-theV terminal set on` which-condnctors, shown collectively as 23;'are terminated: Conductors 23 interconnect the terminal setof selector 22ft0 ay connector shown in Figs. 2-4, so thatuponwtherdescribed advance of wipers W22 a communication channel is extended: from calling station 2,1;tokthevconnector. 'hecompletion ofl the channel isa-lso eieetive'fom-Seiz' dial.

.in the lirst transmitted train of digit impulses.

ing the connector and preparing it to receive directive signals or trains of digit impulses from the calling station Thus the seizing circuit is effective in the Wellunderstood manner for operating calling bridge relay 210 from ground through the upper winding of relay 210, break contacts 202, incoming tip conductor T, the corresponding tip conductors of the preceding selector, line circuit and calling line, the station dial contacts, the ring conductor of the calling line, line circuit, and preceding selector, incoming ring conductor R, break contacts 203, and the lower winding of relay 210 to battery. Relay 210 thereupon operates.

The operation of relay 210 is effective for completing an operating circuit for release delay relay 220 from groundthrough break contacts Z21 of the release magnet ZM21, make contacts 211, and the winding of release delay relay 220 to battery. Operation of relay 220 conneets ground to the incoming conductor S at make contacts 221 in order to mark the tinal selector busy and thereby to guard the connector against seizure by other -exchange equipment subsequently attempting to extend calls through the final selector. The operation of relay 220 also completes an operating circuit for the primary delay relay 300 from ground through make contacts 224, primary off-normal break contacts P22, and the upper winding of relay 300 to battery. The operation of relay 220 also completes an operating circuit for secondary delay relay 420 from ground through make contacts 224,

.secondary oit-normal break contacts S41, and the upper winding of relay 420 to battery. Relays 300 and 420 thereupon operate.

Directive operation of the connector .digit is assumed to comprise tive such impulses, and the second digit six. During the transmission of a train of impulses, relay 220, being a slow release type, remains .operated during the time that relay 210 is released, even though the above-traced operating circuit for relay 220 is opened momentarily at make contacts 211.

Primary direction advance-During the transmission .of the tirst digit, the primary magnet PM31 is energized in response to each release of relay 210 in order to move the wiper set including wipers T1, R1, S1 and HSI away from normal position in the primary direction. The number of steps taken is the same as the number of impulses The advance of the wiper set away from its normal position iS etective for operating primary off-normal means in order to open the above-traced operating circuit for relay 300 at break contacts P22. During the primary direction advance of the wiper set, relay 300, a slow release type, is

held steadily in its operated condition by the intermittent energization of the lower winding of relay 300 in the manner next described. Upon each release of relay 210, a circuit for activating magnet PM31 and the lower winding of relay 300 is completed from ground through break contacts Z21, break contacts 212, operated contacts 226, 425 and 303, and magnet PMSI to battery; the same `ground source is extended through the lower winding of relay 300 to battery. When the transmission of the rst digit has been completed, relay 210 comes to rest in its operated condition. Thus, the above-traced holding circuit for relay 300 and the energizing circuit for magnet PM31 are opened at break contacts 212. Relay 300 restores at this time in order to prepare the selector to re- `ceive the second digit. At this time, the wiper set has been advanced tive steps in lthe primary direction away from its normal position and is at rest opposite the tifth level of terminal sets to which the switch has access.

Secondary direction advance-Upon the transmission of the second digit, the wiper set is advanced in its secondary direction within the selected (fifth) level in order to engage the one of the plurality of terminal sets within the selected level corresponding to the number of impulses in the second digit. Thus, each release of relay 210 during the transmission of the second train of impulses is effective in response to the operation of relay 420 and the release of relay 300 for causing one of a series of energizations of the secondary advancing means including secondary magnet SM31. Each energization of magnet SM31 is effective to advance the wiper set one additional step within the selected level.

During the time that magnet SM31 is being energized, the lower winding of relay 420, a slow release type, also can intermittently be energized so that relay 420 can be made to remain steadily operated even though its upper winding is deenergized. Thus, when the above-traced energizing circuit for the upper winding of relay 420 is opened at break contacts S41 by the operation of the secondary off-normal means (caused by the advance of the wiper set in its secondary direction), relay 420 is maintained operated until after the second digit impulse train has been transmitted to the selector. The circuit for energizing magnet S31 and the lower winding of relay 420 is traced from ground through break contacts Z21, break contacts 212, make contacts 226 and 42S, break contacts 304, and magnet SM31 to battery; the same ground source is extended through an obvious circuit to the lower winding of relay 420 and battery. When the second digit impulses have been transmitted, relay 210 cornes to rest in its operated condition. Thus, the abovetraced circuit for energizing the lower winding of relay 420 and magnet SM31 is opened at break contacts 212. Relay 420 thereupon releases. n

Busy test.-At the conclusion of the transmission of the tirst and second digits to the connector, it is seen that the wiper set comprising wipers T1, R1, S1 and HS1 has been advanced into engagement with a particular set of terminals. Each terminal set to which the wiper set has access is normally in an idle condition and ready to be seized by switching equipment such as the nal selector vtion of a busy indicating ground potential over a conductor, such as S2, to the one of the terminals in the selected set which is engaged by wiper S1.

Upon the advance of the wiper set into engagement with any one of the terminal sets, means comprising relay 310 within the nal selector is eiective for conducting a test in order to determine whether or not the selected terminal set is in busy condition. Thus, during the time interval between the transmission of the last impulse of the second train of digit impulses to the connector has been completed and the release of the slow release type relay 420, contact means on relay 420 is effective for extending a connection from the one of the terminal sets to which busy indicating potential may be connected and the winding of the relay 310. Assuming for the moment that the selected terminal set is in busy condition, ground potential present on conductor S2 and wiper S1 is extended through make contacts 423, break contacts 419, and the winding of relay 310 to battery. The subsequent release of relay 420 (described above) opens the above-traced operating circuit at make contacts 423. Thus, it is seen that if relay 310 is to operate at this time, it must be during the interval that relay 420 is in its operated condition.

The operation of relay 310 and the release of relay 420 is effective for closing a holding circuit for relay 310 from ground through make contacts 225 and 317, break contacts 424 and 419, vand the winding of relay'310 to battery. The operation of relay 310 is effective in re- S Spouse to the released condition of switching relay 410 (the `fmunction'of `which is -to be morefully `explained in they following paragraphs) for c-ompleting a circuit to connect busy indicating tone `to the calling telephone stationpZwl. Thelatter circuit is traced from the grounded busy tone Source (not shown) through break 4contacts 42,1, make contacts 312 break contacts 4:12a, the upper weintding'ofY answer bridge relay 200, break contacts 411a, blocking capacitor C21, break contacts 292, conductor Ththe above-traced connection to calling station 21, conductor R, break contacts'203, and thelower winding of relay'rZlll to battery.` The operation of relay 310 is also eifectivev for opening the operating circuit of.I switching relay 410 at break contacts 316 for reasons "thaty are to be explained presently.

In the event that busy indicating ground potential is absent from the terminal connected to conductor S2, relay V310fails to operate. Upon the release 'ofsecondary delay relay 420 following the-completionfof transmission othesecond digit to the linal selector and inresponseto thereleasevd conditionA of relay v31)-thefcforinector isprepared: forv switchthrough operation where the vcomriiunication channel between the connector andrthe calledstation is 'partiallyV completed. This so-called"` switchthrough operation is next described;

Switchthr'ough operatz'0r`i-..-In response to the release of relay 4201 andfthe unoperatcd condition of relay 310, a circuit for operating switching relay 410, is completed as follows: from battery through a, resistance within line circuit 42, 'conductor S2, wiper S1, break contacts 422, the lower Winding of relay 4:10, break contacts 3 16and make contacts '225r to ground. The energizationof, the lower winding of relay- 410; is eiiective for causing thev operation of preliminary make contacts 417 which thereuponcompletes a 'circuit forgfully operating relayj410. The latterfcircuit is traced from ground through make contactsy 224, make contacts 417 andftlieupper winding of relay 410 to battery. The operation of relay 41()V is eiectivefor extending a communication channel frgornthe iinal selector signaling apparatus -to the calledflinerstation 4;inth e mannertobedescribed. The operation of relay 451i)y is also effective ,for placyingdirectgroundj on Wiper S1 and a correspondingv terminalfof the engaged terminal set at make contacts'll inforder to'fmark the equipment connected tothe selected terminal set A'a'sbusy toother equipment within the exchange. N

MReturningfto Vthe consideration of, relay 310i it isseen that the operation of relay 310 inresponse to the'busy condition ofQthe called line terminal seti's, eiiectivejfor opening 'the above-traced energizing circuitr :forjthe lower winding of`relay 4'10"at breakcontacts' 316,; This hasA the eiect of preventing the operation'ofY switching relay 41,1),and avoids the possibility ot extendingvthe communication channelthrough the iinal selectortov a, busy Vterminalfset.'` Similarly, the operation of relay "4104is` elec'tive for opening'the, above-traced operating circuit forf"r'elay 310;l atjbreak contacts 419' in order to prevent `thejopera tion oi' relay` 310 A' over the v above-traced: busy tes-t 'circuit attei-l tlie switchtliroughoperation has vtaken plaee. Signaling the called line A ringing generator common to aplurality of connectors such as the one being described here'is provided for. furnishinglow frequency alternating current* signals in -thefwell-knowri= manner to the signaling dev-ice suchlas a ringer at vtliecalledtelephone stationf FollowingI the operation'of switching relay 410, a circuit is. prepared for completing a connectionfbetween the ringing generator androne of the-conductors 'such as R2 connected to tiie terminal of the set-engagedl bythe wiper set. Duringthe time-thai; reiiaysio is operated (in the` manner tothe explained) the circuit; is traced froml ringing generator through make contact 31S, the upper winding ofz relay 40,0i break contacts 404a,make contacts, 414,*,and wiper R1` to conductor R2,v During the time'that-,relayltl` is released, the above-traced circuit from. the 'upper'winding pcd ce path is eiective for closing an operating circuit of relay 400 to conductor R2 is connected to battery through break contacts 314 on relay 310. Thus, it is-seen thatthe reoperationof relay 310 is effective in response to the operationof relay 410 for completing the abovetracedl circuit including the ringing generator.

telephone 4310i;` line 45, the appropriate signal M ctoris.e'cciinected'4 toone of the terminals of the selectedset whicliisralso individual to station 43. The code'signal'is thereupon transmitted to the Winding of relay 310 Within the connectorin order to operate relay 310 during the time thatrthe appropriate signal is being st c.

`transmittedover theline connected to the selected terminaliset'." Suclifa connection may be traced from signal le'a`d`44, to conductor H82, Wiper HSI, break contacts 4.98, make contacts41f8, and the winding of relay 310 tobattry."

After tlieri'nger` offmthe called station 43 has been operatedand the stationtelephone is removed `from its hooksw' h, the well-known, ring trip circuit comprising a low impedance pathbetweenconductors T2 and R2 is completedat then station.` v' The'completion of the low imfer ring trip relay 4,0()` which is traced from ground thfrou hgbreak contacts 40M, make contacts 411b, wiper T1, 'conductor T2, the low impedance path between conduetorslTZand' R2,y conductor R12, wiper R1, make conf tactsf414,"break contacts 404a and the upper winding of re'lay 460'., In fvthe event that relay 310is in its unoperatedcon'dition at this time, the circuit is completed to battery through break contacts 314. relayn310 is in operated condition at this time, the circuitfhfoijoperatingf'relay 40G isl completed through the c lirectg current p "artfofO the ringingv generator by wayof niakecontactsals.4

V"The completion of the above-traced circuit for relay eiiective'lfor energizing that relayto the point Wliercpreliminary make contacts 4'07 are closed; The

closing4 lofcontacts* 40T completes an operating circuit formrelaiyV 300"Wover the vfollowing circuit: from ground through make-V contacts 2 24 andi-107,` break contacts 405 1a"rig`i`ftliez'upperAV winding ofy relay 300 to battery. Relay thereuponoperatesi The operation of relay 300 is eiective "for 'closing an operating -circuit `for the lower windingfof*relayl 400 froii'i'ground through` make contacts 2224"842, andj`3`02 and the lower winding of relay 4 0()toba-tteryl`,` Relayv 400 thereupon operates to close a locking: circuit for'itselfl from ground through make contacts"224, 407, and 406 and the lower winding of relay 400` to 'batteryi The 'operation of relay 400 is eiective for v opening the above-traced circuit for reoperating relay 300 at break contactslttl. Relay 300 thereupon releases. il'lheoperation' ofir'elay 400 is effective for disconnecting wiper'PISlv from its; above-traced connection to the Win'difgforelaySl Relay 310 thereupon stops followiiig code vsignals transmitted over 'conductor HSZ. 'Ih'efoperationof relay40g)v is effective for completing an operating'circuitl for answer bridge relay 200. The circuit` istra'ced from ground through make contacts 412b, the upper winding of relay 200, make contacts 40-1flan'd' 411'b,V wiper T1, conductor T2, the loop o'f the station 43', conductor R2, wiper R1, make contacts 414, 404B; 413, and v402]) and the lower winding of relay 200' tobattery. Relay 20 0 thereupon operates in order to"reverseitlie direction of current flow through conductors T and R to calling station 21 at reversing contacts 20132D2103, and 204;

In the event that The operation of relay 400 is also effective'for com pleting a communication channel through the final selector from the incoming conductors T and R to wipers T1 and R1, respectively, and thereby is effective to interconnect the calling station 21 to the called station 43. In the case of the tip side of the communication channel, the circuit is traced from incoming conductor T through make contacts 201, blocking capacitor C22, break contacts 313, make contacts 404b and 414 and Wiper R1. The ring side of the channel is traced from incoming conductor R through make contacts 204, blocking capacitor C21, break contacts 311, make contacts 40111 and 411b and wiper T1. Conversation then takes place and may continue between calling station 21 and called station 43 until the parties hang up or until conversation through the connector is forcibly ended. The forced ending or conversation timing operation is next described.

Conversation timing In addition to the process of reversing the direction of current flow over the loop of the calling telephone station, the operation of relay 200 is effective for starting the conversation timing cycle by connecting the common timing lead TPI to the Winding of timing A relay 320. The circuit is traced from conductor TP1 through make contacts 206, break contacts 325 and 336 and the Winding of relay 320 to battery. Another interrupter common to a plurality of connectors of the type being described is effective for placing direct current signals in a particular sequence on conductors TPI, TPZ, H1, H3, and CWT. The sequence in which these signals appear is described in the following paragraphs. Upon the appearance of the tirst ground signal connected to conductor TPI occurring after relay 200 operates, relay 320 operates over the above-traced circuit and closes a locking circuit for itself from ground through make contacts Z21 and 326, break contacts 336 and the winding of relay 320 to battery.

The operation of relay 320 is effective for connecting conductor TP2 to the winding of timing relay 330. The circuit is traced from conductor TF2 through make contacts 324, break contacts 335 and the winding of relay 330 to battery. Upon the next appearance of a momentary ground signal on conductor TP2, relay 330 is operated and establishes a locking circuit for itself from ground through make contacts 205 and 334 and the winding of relay 330 to battery.

The operation of relay 33t) is effective for transferring relay 320 from its above-traced locking circuit including make contacts 326 to a connection to rst holding conductor H1. The latter circuit is traced from conductor H1 through make contacts 327 and 337 and the winding of relay 320 to battery. Thereafter, relay 320 is held in its operated condition from a ground signal present on conductor H1 at the time relay 33t) operates. Upon the completion of a cycle of operation of the other interrupter, the ground signal is momentarily removed from conductor H1 so that relay 320 releases. The release of relay 320 and the operation of relay 330 is effective for connecting common timing conductor H3 and the Winding of relay 310. The circuit is traced from conductor H3 through make contacts 332, break contacts 319 and 321, make contacts 331, 469 and 418, and the winding of relay 310 to battery. Upon the appearance of the next ground signal on conductor H2, relay 310 reoperates.

The reoperation of relay 310 is effective in response to the operation of relays 400 and 331 for establishing for itself a locking circuit from ground through make contacts 224 and 318, break contacts 321, make contacts 331, 409, and 41S and the winding of relay 310 to battery. At this time, recperated relay 310 is further elective for opening the above-traced communication channel through the connector at break contacts 311 and 313, thereby blocking the talking channel established from 200 operates.

calling station 21 to called station 43 at the end of a predetermined time interval measured from the time relay It is to be noted that the operation of relay 414) is effective at this time for preventing the application of busy tone to the calling station 21 by opening the above-traced circuit for applying busy tone at break contacts 412a. Similarly, the operation of ring trip relay 400 is effective for making those contacts on relay 310 including contacts 314 and 315 which were effective for applying signaling current to the called station 43 inetective by opening the previously traced circuit for applying signaling generator to the called station at break contacts 40411.

Release by the subscribers At any time during the course of the extension of a connection from the calling to the called station, the calling station 21 controls the release of the connector. Thus, when the telephone at calling station 21 is returned to its hookswitch, relay 210 is released for a time interval sufficient to allow relay 220 to release. The release of relay 220 is effective for removing ground from the previously traced holding circuit of relays 400 and 410 at make contacts 224. Relays 400 and 410 thereupon release. The release of relay 410 is effective for closing an energizing circuit for release magnet ZM21. The circuit is traced from ground through break contacts 415 and 222, parallel off-normal make contacts P21 and S21, and the winding of magnet ZM21 to battery. The energization of magnet ZM21 restores the wiper set from its advanced primary yand secondary positions to normal position.

The release of relay 220 is also effective for removing ground from the previously traced locking circuit of relays 310, 320, and 330 at make contacts 221 and 225 so that the latter are similarly restored in the event that they had been operated at the time relay 220 releases. The release of relay 220 is further effective for removing ground from incoming sleeve conductor S at contacts 221 in order to remove the busy condition from the connector and thereby make the connector available for the extension of other calls.

While I have shown and described a particular embodiment of my invention, it will be obvious to those skilled in the art that changes and modifications may be made without departing from the spirit of my invention in its broader sense. I therefore aim in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of my invention.

What I claim is:

1. In a telephone system, a connector including a switch, said switch having a wiper set and a plurality of terminal sets for engagement by said wiper set, means connected to each of said terminal sets for independently changing each terminal set from its normal idle condition to busy condition, means for directively advancing said wiper set into engagement with any one of said terminal sets in order to select one of said terminal sets, a multi-purpose relay having a pluarlity of contacts, means operative following the engagement of one of said terminal sets by said wiper set for controlling said relay to indicate the busy or idle condition of the selected one of said terminal sets, means for preparing a communication connection through said selector by way of said wiper set to any one of said terminal sets, means including certain of said contacts for rendering said connection preparing means inoperative in the event said relay indcates the selected one of said terminal sets is in busy condition, a source of signaling current, means including certain other of said contacts for connecting said source to the selected one of said terminal sets in order to transmit distinctive signals to the selected one of said terminal sets, means for transmitting supervisory signals to any one of said terminal sets, means operative in response to the receipt of a supervisory signal subsequently transmitted to the selected one of said terminal sets and to said selector for rendering said signaling current connecting means ineffective and for completing said communication connection through said wiper set to the selected one of said terminal sets, means for transmitting timing signals to said connector, means operative in response to the operation of said supervisory signal responsive means for causing said relay to be controlled by said timing signal source, and means including still other contacts on said relay for preventing the transmission of communicating signals through the communication connection of said conector.

2. The telephone system set forth in claim l wherein said means for causing said relay to be controlled by said timing source is operative in response to the operation of said connection preparing means in order to prevent said relay from operating from timing signals during the period when signaling current is being transmitted to the selected one of said terminal sets.

3. In a telephone system, a connector including a switch, said switch having a wiper set and a plurality of terminal sets for engagement by said wiper set, each of said terminal sets including a particular terminal, means connected to each of said terminal sets operative for connecting a busy indicating potential to said particular terminal of the corresponding set in order to change the set from its normal idle condition to busy condition, means for directively advancing said wiper set into engagement with any one of said terminal sets in order to select one of said terminal sets, a multi-purpose relay having a winding and a plurality of contacts, means operative upon the engagement of any one of said terminal sets by said wiper set for connecting said particular terminal of the selected set to said relay winding, said relay thereupon being operative in response to the application of busy potential to its winding for indicating a busy condition on the selected one of said terminal sets, means for preparing a communication connection through said connector by way of said wiper set to the selected one of said terminal sets, means including certain of said contacts operative in response to the operation of said relay for rendering said connection preparing means inoperative in order to prevent the extension of a connection through said connector to a busy one of said terminal sets, a source of signaling current, means comprising certain other of said contacts operative in response to the operation of said relay for connecting said source to the selected one of said terminal sets, a source of control signals, said connection preparing means being also operative for connecting said control signals to the winding of said relay in order to cause distinctive signals to be transmitted to the selected one of said terminal sets, means for transmitting a supervisory signal to any one of said terminal sets, means operative in response to the transmission of a supervisory signal to said connector through said wiper set and the selected one of said terminal sets for disconnecting said certain other contacts in said signaling current source from the selected one of said terminal sets, for disconnecting said control signal source from the winding of said relay, and for completing the communication connection through said selector, means for transmitting timing signals to said connector, means operative in response to the' operation of said supervisory signal responsive means for connecting said timing signal source to said relay winding in order to operate said relay a predetermined time interval following the receipt of a supervisory signal, and still other of said contacts eiective in response to the operation of said relay and said connection preparing means for opening said communication connection in order to prevent the transmission of signals through said communication connection a predetermined time interval following the receipt of a supervisory signal.

4. In a telephone system, a connector including a switch, said switch having a wiper set and a plurality of terminal sets for engagement by said wiper set, each of said terminal sets including a particular terminal, means connected to each of said terminal sets operative for connecting a busy indicating potential to said particular terminal of the corresponding set in order to change the set from its normal idle condition to busy condition, means for directively advancing said wiper set into engagement with any one of said terminal sets in order to select one of said terminal sets, a multi-purpose relay having a winding and a plurality of contacts, a relay momentarily operative upon the engagement of one of said terminal sets by said wiper set for connecting said particular terminal of the selected one of said sets to said relay winding, said multi-purpose relay being operative in response to the application of a busy indicating potential to its winding and nonoperative in the absence of a busy indicating potential to said winding, means for thereafter maintaining said multi-purpose relay in operated condition, a communication connection through said connector by way of said wiper set to the selected one of said terminal sets, a switchthrough relay operative for partially completing said communication channel, means including certain of said contacts operative in response to the operation of said multi-purpose relay for rendering said switchthrough relay inoperative in order to prevent the extension of a connection from said connector to a busy one of said terminal sets, a source of signaling current, means including certain other of said contacts operative in response to the operation of said multi-purpose relay for connecting said signaling current source of the selected one of said terminal sets, a source of control signals, said switchthrough relay being operative for connecting said control signal source to said multipurpose relay winding in order to transmit distinctive signals to the selected one of said terminal sets, means for transmitting supervisory signals to the selected one of said terminal sets, said signaling current selecting means including a ring trip relay operative in response to a supervisory signal subsequently transmitted from the selected one of said terminal sets to said connector for disconnecting itself and said signaling current source from the selected one of said terminal sets, for disconnecting said control signal source from said multi-purpose relay winding, and for completing said communication connection, means for transmitting timing signals to said connector, means operative in response to the operation of said switchthrough and said ring trip relays for connecting said timing signal source to said multi-purpose relay winding, and still other of said relay contacts operative in response to the operation of said multi-purpose relay and said switchthrough relay for opening said communication connection in order to prevent the transmission of signals through said communication connection a predetermined time interval following the receipt of a supervisory signal.

References Cited in the tile of this patent UNITED STATES PATENTS 2,701,278 Pharis Feb. l, 1955 

